Researchers believe stronger bones in newborns can be attributed to vitamin D levels, according to a new study into sun exposure where pregnant women's exposure to sunlight was found to have a direct impact on the height and size of babies.
Studying meteorological data from their mothers' last three months of pregnancy, as well as height measurements and the results from bone density scans, the cases of nearly 7000 children were examined at The Avon Longitudinal Study of Parents and Children at Britain's University of Bristol
When compared to children born in the darkest months, children born to mothers with the highest levels of sun exposure were reported to be 0.5cm taller and showed extra bone area (over and above that which their additional height might cater for).
The results can be attributed to vitamin D levels, say researchers. This is due to the reaction of sunlight on the skin which generates vitamin D, which then works with calcium to build bones.
According to the researchers, even in the womb vitamin D is important for bone building.
Vitamin D levels in the blood of 350 women in the study in their 37th week of pregnancy were also examined – and the results closely correlated with levels of sun exposure.
As Jon Tobias, Professor of Rheumatology at Bristol University, commented: "Wider bones are thought to be stronger and less prone to breaking as a result of osteoporosis in later life, so anything that affects early bone development is significant."
"Pregnant women might consider talking to their doctor about taking vitamin D supplements, particularly if their babies are due… when sunlight levels are low."